Typically, marker posts are supported either in or above the soil and have an upward extending member to alert the person to a potential hazard proximate the post. Some posts may either display information thereon while in other cases the mere presence of the post alerts a person to a hazardous or dangerous condition. Typically, the marker posts are made from a polymer plastic or other material capable of withstanding the elements for a period of years.
Landes U.S. Pat. No. 7,025,016 shows an example of a one-piece triangular shaped marker post having anchoring flaps to retain the marker post in the soil. One of the problems associated with marker posts is that oftentimes the marker posts are located in areas where the post may be subject to impacts from either animals or vehicles, which can cause the post to bend. The impact can cause the marker post to lose its ability to return to the normal upright condition.
Landes U.S. Pat. No. 6,099,223 shows an example of a marker post, which can return to its original shape through the use a triangular shaped resilient post that includes corner webs, which facilitate the restoring of the marker post to an upright condition when the post is bent by an impact.
U.S. Pat. No. 4,571,118 shows an example of a tubular shaped marker post, which also facilitates the restoring of the marker post to an upright condition when the post is bent by an impact. While the Landes U.S. Pat. No. 6,099,223 discloses the use of corner webs to facilitate the restoring of the marker post to an upright condition the U.S. Pat. No. 4,571,118 uses a simulated tubular shaped marker post having a stiff concentrically positioned resilient rod which supports a plurality of thin walled bulbs in an end-to-end condition along the exterior of the rod. The ends of each of thin walled bulbs form a tight fit with the concentrically positioned resilient rod so that when the bulbs are impacted by an object the compression of air within the bulbs prevents a sharp impact between the colliding object and the rod. The U.S. Pat. No. 4,571,118 points out that by preventing fracturing contact between the rod and the impacting object the rod can return to its straight orientation. A hole in each of the thin walled bulbs allows a gradual ingress of air into the interior of the bulbs allowing the bulbs to return to their original shape.
U.S. Pat. No. 4,611,949 shows another type of marker device wherein the marker post is supported by a detachable base with the detachable base being able to support and stabilize the simulated tubular shape markers shown in U.S. Pat. No. 4,571,118.
Although there are existing marker posts that can return to an original upright condition when impacted the formation of a marker post with internal webs can be difficult and costly to make. Similarly, the formation of a simulated tubular post with thin walled bulbs, which are supported in an end-to-end condition on a central support rod, can also be costly to make as well as providing less space for visual information. In addition some marker posts may fail to return to the upright condition when subjected to repeated impacts.